1. Field of the Invention
This invention relates to a method for coating textile substrates such as carpets and textile fabrics with an improved latex-containing coating composition.
2. Description of the Prior Art
In the manufacture of coated textile substrates such as tufted carpets, a liquid coating composition containing latex normally is applied to the back of the carpet and the resulting laminate is heated in an oven to dry the backing layer and bond it to the carpet. The latex backing serves to lock the tufts into the carpet substrate, and to provide adhesions for the jute or foam layer which can be laminated to the back of the carpet. The latex backing layer also imparts to the carpet the desired hand characteristics, adds dimensional stability, adds weight to the carpet, acts to promote fire retardancy, and fills in the space between the stitches. One latex coating can comprise the total backing operation in some cases. If a secondary foam layer is applied, a latex composition similar to the undercoat composition may be employed.
Latex carpet backing compositions are presently formulated on the basis of 100 parts by weight of dry latex. Included in the standard formulations are up to 800 parts of filler. Prior art attempts to reduce the cost of these latex coating compositions in the carpet backing and fabric coating industries has almost always involved the use of increased amounts of filler. There also have been some attempts to extend (i.e., replace a portion of) the latex solids with starches, hydrocarbon oils and waxes. These prior art extenders suffer from the drawbacks of decreasing the fire retardancy of the article thus requiring increased amounts of fire retardants such as aluminum trihydrate (a filler), phosphates, borates, halogens, antimony oxidex and the like. This increase in fire retardant offsets any cost advantage from extending the latex with the prior art extenders.
Thus, it would be of great value and represent significant monetary savings if a latex extender could be found which does not adversely effect the properties of the latice including, inter alia, fire retardancy. Moreover, since most latex solids are petroleum based products, a significant reduction in utilization of these increasingly scarce materials will have an obvious beneficial impact on our natural resource picture.